Saudi Arabia has said its initial inquiries indicate that Iranian weapons were used in attacks on key oil installations, and it will invite UN and other international experts to take part in the investigation.
Following the assault on a key processing plant and another oil field, the Saudi ministry of foreign affairs said: “The kingdom will take the appropriate measures based on the results of the investigation, to ensure its security and stability.”
The ministry added that Saudi Arabia “affirms that it has the capability and resolve to defend its land and people, and to forcefully respond to these aggressions”.
It called Saturday’s attack, which resulted in the suspension of approximately 50% of Saudi Aramco’s production and was initially blamed on Houthi rebels from neighbouring Yemen, “an unprecedented act of aggression and sabotage” and “egregious crime which threatens international peace and security”.
US president Donald Trump earlier said it is “looking like” Iran was responsible for the attacks – but he says he does not want war.
Mr Trump said at the White House that the US is not looking at retaliatory options until he has “definitive proof” that Iran was responsible.
However, the president told reporters in the Oval Office that the US “is prepared” if the attacks warrant a response.
US secretary of state Mike Pompeo also said “emerging information indicates that responsibility lies with Iran”.
Iran has denied involvement, though it comes amid heightened tensions over Tehran’s unravelling nuclear deal with world powers, including the US, which pulled out of the deal last year.
Mr Trump said Mr Pompeo will be travelling to Saudi Arabia in due course.
American officials also released satellite images of the damage at the heart of the kingdom’s crucial Abqaiq oil processing plant and a key oil field. They said the attackers used multiple cruise missiles and drone aircraft.
The Americans alleged the pattern of destruction suggested Saturday’s attack did not come from neighbouring Yemen, as claimed by Iranian-backed Houthi rebels there.